System and method for configuring contents of network management notifications

ABSTRACT

A method for configuring contents of a network management notification includes receiving at a management station a list of notifications supported by an agent and sending a message to the agent specifying objects for each of the notifications. A notification containing the specified objects is received at the management station upon the occurrence of an event.

BACKGROUND OF THE INVENTION

The present invention relates generally to network management, and moreparticularly, to configuring the contents of an SNMP notification.

It is desirable to manage and control nodes of a network such as aTCP/IP network from one or more network management stations connected tothe network. The network management stations monitor and control othernodes in the network including hosts, routers, etc. A protocol known asthe Simple Network Management Protocol (SNMP) is used to communicatemanagement information between network management stations (NMS) andSNMP agent software operating on other network nodes, or the same nodeas the network management station. SNMP is described in Case, RFC 1157,“A Simple Network Management Protocol (SNMP),” (Internet EngineeringTask Force May 1990), the contents of which are incorporated byreference herein. Using SNMP in a TCP/IP network, a network managementstation may monitor traffic at a remote node and modify networkoperation parameters at the remote node.

FIG. 1 is a block diagram illustrating an exemplary network utilizingSNMP. The network includes at least one management station 10 whichcontrols a plurality of nodes such as workstation 11, bridge 12, router14, printer 15, or other peripheral devices (e.g., personal computers,hubs, repeaters). The management station 10 includes a SNMP manager 16(command generator and notification receiver). In order for an SNMPmanagement station 10 to manage a node, the node must be able to run anSNMP agent 17 (command responder and notification originator), which isan SNMP management process typically encoded in software (some nodes mayuse a hardware implementation).

To facilitate SNMP operation, nodes of the network including the networkmanagement stations 10 maintain network management information databasesknown as MIBs (management information bases) 18. MIBs are described inMcCloghrie, et al., RFC 1213, “Management Information Base for NetworkManagement of TCP/IP Based Internets: MIB-II” (Internet Engineering TaskForce March 1991), the contents of which are incorporated by referenceherein.

The MIB 18 at each node consists of many individual objects, each havingone or more instance. Each instance has a single value. For example, aparticular node may include within its MIB an object whose valuespecifies the total number of IP datagrams received at that node,including those received in error. Each MIB 18 includes a large numberof such objects. The object instances and their corresponding values arecarried in packets called protocol data units (PDUs) and containoperating parameters, statistics, and control information for theelement and its components.

Each MIB object is uniquely identified by a series of integers called anObject Identifier (OID). For example, the object ifinOctets isrepresented by the OID 1.3.6.1.2.2.1.10. The can be many instances of anobject in existence on an agent. For example, there is one instance (andvalue) of ifInOctects for every physical interface known to the agent.Each instance is identified by appending one or more additional integersto the OID (e.g., 1.3.6.1.2.1.2.2.1.10.x, where x is an integer greaterthan zero). The first element of this specific OID identifies an overallobject identifier domain allocated to the ISO. The second element hasthe value 3 which is defined as indicating allocation toward anorganization under the auspices of the ISO. The third element identifiesthe US Department of Defense (DOD) as the responsible organization. Thefourth element has the value of 1 and identifies the Internet. The fifthelement indicates that the identifier is used for management. Theremaining elements identify the particular object types with greaterspecificity.

The organization of objects within an MIB may be illustrated as a treestructure. An example of a portion of such a tree structure isillustrated in FIG. 2. The leaves of the tree instances of individualobjects. FIG. 2 shows the MIB tree from its root, “ISO”, to some of itslower branches. A first branch 21 of primary interest includes thestandard MIB objects defined by RFC 1213. A second branch 23 includesMIB objects defined for use by Cisco Systems. The illustration of FIG. 2does not extend down to individual leaves but rather indicates theprefix of elements in OIDs for various classes of objects. For example,OIDs from MIB objects pertaining to TCP would begin with 1.3.6.1.2.1.6.

The management station communicates with the agents over the networkusing the SNMP protocol, which allows the management station to querythe state of the agent's local objects and modify them if necessary.SNMP is a request-response protocol by which the variables of an agent'sMIB may be inspected or altered. The protocol is described in RFC 1905,“Protocol Operations for Version 2 of the Simple Network ManagementProtocol”, Case, McCloghrie, Rose & Waldbusser, January 1996, thecontents of which are incorporated by reference herein.

A typical SNMP operation involves management station sending an SNMPmessage to agent requesting a particular local parameter. The agent thenrecovers this parameter by accessing a particular object in the MIB andresponds to the request with a reply to the management station includingthe parameter value. SNMP operations are defined on a list of MIBvariable instances called a variable binding (varbind) list. Eachelement of a varbind list describes a specific MIB variable instance. Avarbind element specifies three MIB instance attributes: its objectidentifier, data type, and value.

The management protocol provides for the exchange of messages whichconvey management information between the agents and managementstations. For example, the management station may send a request to anagent asking it for information or commanding it to update its state ina certain way. The agent typically replies with the requestedinformation or confirms that it has updated its state as requested.Conventional message types include Get, GetNext, GetBulk, Set, Trap, andInform. The Get operation is used by the system to retrieve the value ofone or more object instances from an agent. The GetNext operation isused by the system to retrieve the value of the next object instance ina table or list within an agent. The GetBulk operation is used by thesystem to efficiently retrieve large blocks of data, such as largetables. The Set operation is used by the network management station toset the values of object instances within an agent. The Trap operationis used by agents to asynchronously inform the network managementstation of a event of interest to one or more network managementstations. Notification originators can generate informs, which arenotifications that should be acknowledged by notification receivers. Inan acknowledgement is not received within a configurable time-window,the notification originator attempts to resend the inform up to amaximum of N returns, where N is a configurable integer. The Trap andInform operations may be used to send notifications to the manager.

Notifications are unsolicited messages sent from an agent to the SNMPmanager to apprise the manager of network events. SNMP notificationsallow the agent to initiate communication with management applicationswhen an event of interest to one or more network management stationstakes place. These events include cold start, warm start, link down,link up, authentication failure, neighbor loss, and enterprise. SNMPnotifications contain a sequence of SNMP objects that typically providecontext information on why each notification was generated.

Many networks contain components manufactured by several differentcompanies. In order for the management station to communicateeffectively with these varied devices, the information maintained by theagents must be rigidly specified. SNMP therefore describes the exactinformation each agent 17 must maintain and the format in which it mustbe maintained in the MIB 18. At times, newer versions of MIBs result innew objects being added to notifications. Also, notifications are oftengenerated with different variable bindings than those that should belisted in the MIB, either in error or because a network element has notkept up with newer versions of MIBs. Furthermore, it is often desirableto add specific objects to a notification to provide additionalflexibility in management of a network.

There is, therefore, a need for a system and method for instructing anagent which objects to send for each notification so that notificationscan be easily reconfigured by a management station.

SUMMARY OF THE INVENTION

A method and system for configuring contents of network managementnotifications are disclosed.

A method of the present invention includes receiving at a managementstation a list of notifications supported by an agent and sending amessage to the agent specifying objects for each of the notifications. Anotification containing the specified objects is received at themanagement station upon the occurrence of an event at the agent.

The messages may be sent using SNMP protocol. The list of notificationsand objects may be transferred between the management station and agentin the form of a management information base. The notifications may besent to the management station as a Trap or Inform message.

In another aspect of the invention, a method for sending SNMPnotifications from an agent to a management station comprises receivinga message from the management station specifying objects for eachnotification supported by the agent. The agent then modifies a list ofobjects for each of the notifications and sends a notificationcontaining the specified objects upon occurrence of an event.

A computer program product of the present invention comprises code thatreceives at a management station a list of notifications supported by anagent, code that sends a message to the agent specifying objects foreach of the notifications, and code that receives a notificationcontaining the specified objects. The product further includes acomputer-readable storage medium for storing the codes.

A system of the present invention includes a processor that receivesinformation specifying contents of notifications supported by an agentwithin a network at a management station and sends instructions from themanagement station to the agent to modify the contents of thenotification to a preferred configuration. The system further includes astorage medium having the preferred configuration stored thereon.

In another aspect of the invention, a system for configuring thecontents of a network management station comprises means for receivinginformation specifying contents of notifications supported by an agentwithin a network at a management station and means for sendinginstructions from the management station to the agent to modify contentsof the notifications.

The above is a brief description of some deficiencies in the prior artand advantages of the present invention. Other features, advantages, andembodiments of the invention will be apparent to those skilled in theart from the following description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary network utilizing anetwork management protocol.

FIG. 2 is a schematic illustrating a portion of a tree structure used tospecify MIB object identifiers.

FIG. 3 is a schematic illustrating an example of a computer system thatcan be utilized to execute software of an embodiment of the presentinvention.

FIG. 4 is a system block diagram of the computer system of FIG. 3.

FIG. 5 is a schematic of a router which may represent a network nodeaccording to the present invention.

FIG. 6 is a flowchart illustrating a process for defining objects for anotification.

FIG. 7 is an example of a notification table specifying thenotifications an agent supports.

FIG. 8 is a notification variable binding table specifying the variablebindings the agent is configured to send for each of the notificationslisted in the table of FIG. 7.

FIG. 9 is a portion of a modified notification variable binding tablesent to the agent to instruct the agent how to configure notifications.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The following description is presented to enable one of ordinary skillin the art to make and use the invention. Descriptions of specificembodiments and applications are provided only as examples and variousmodifications will be readily apparent to those skilled in the art. Thegeneral principles described herein may be applied to other embodimentsand applications without departing from the scope of the invention.Thus, the present invention is not to be limited to the embodimentsshown, but is to be accorded the widest scope consistent with theprinciples and features described herein. For purpose of clarity,details relating to technical material that is known in the technicalfields related to the invention have not been described in detail.

The present invention operates in the context of a data communicationnetwork including one or more multiple nodes. Nodes of a network may beuser workstations, servers, routers, etc. Certain nodes of the networkmay be network management stations (NMS) 10 used to monitor and controloverall network operation (FIG. 1). As described below, the method andsystem of the present invention allow a management station 10 todynamically add new objects to a notification and reorder the objects inthe notification so that the management station receives specificinformation from an agent 17 upon the occurrence of an event. Thisallows system administrators to tailor notifications to meet specificneeds of a network. The present invention further provides a method fordetermining the objects contained within a device's notification beforea notification is received by the management station 10.

FIG. 3 illustrates an example of a computer system that may be used toexecute software of an embodiment of the invention. The computer system20 includes a display 22, screen 24, cabinet 26, keyboard 28, and mouse30 which may include one or more buttons for interacting with a GUI(Graphical User Interface). Cabinet 26 houses a CD-ROM drive 32, systemmemory 42 and a hard drive 44 (see FIG. 4) which can be utilized tostore and retrieve software programs incorporating computer code thatimplements aspects of the invention, data for use with the invention,and the like. Although CD-ROM 34 and floppy disk 35 are shown asexemplary computer readable storage media, other computer readablestorage media including tape, flash memory, system memory, and harddrive may be utilized. Additionally, a data signal embodied in a carrierwave (e.g., in a network including the Internet) may be the computerreadable storage medium.

FIG. 4 shows a system block diagram of computer system 20 used toexecute software of an embodiment of the invention. Computer system 20further includes subsystems such as a central processor 40, systemmemory 42, fixed storage 44 (e.g., hard drive), removable storage 46(e.g., CD-ROM drive), display adapter 48, sound card 50, transducers 52(speakers, microphones, and the like), network interface 54, andprinter/fax/scanner interface 56. Other computer systems suitable foruse with the invention may include additional or fewer subsystems. Forexample, computer system 20 may include more than one processor 40(i.e., a multi-processor system) or a cache memory.

The system bus architecture of computer system 20 is represented byarrows 58 in FIG. 4. However, these arrows are only illustrative of onepossible interconnection scheme serving to link the subsystems. Forexample, a local bus may be utilized to connect the central processor 40to the system memory 42 and display adapter 48. Computer system 20 shownin FIGS. 3 and 4 is only one example of a computer system suitable foruse with the invention. Other computer architectures having differentconfigurations of subsystems may also be utilized.

Some of the nodes in a network that employs the present invention may benetwork devices such as routers and switches. For example, some of thenodes may be specially configured routers such as those available fromCisco Systems, Inc. of San Jose, Calif. A general architecture for someof these machines will appear from the description given below. In analternative embodiment, a router or switch may be implemented on ageneral purpose network host machine such as the computer system ofFIGS. 3 and 4.

Referring now to FIG. 5, a router 60 suitable for implementing thepresent invention includes a master central processing unit (CPU) 61,interfaces 68, and a bus 65 (e.g., a PCI bus). As shown, CPU 61 includesa memory 62 and a processor 63. When acting under the control ofappropriate software or firmware, CPU 61 is responsible for such routertasks as routing table computations, network management, and generalprocessing of packets. It preferably accomplishes all these functionsunder the control of software including an operating system and anyappropriate applications software. CPU 61 may include one or moreprocessors 63 such as a processor from the Motorola family ormicroprocessors of the MIPS family of microprocessors. In an alternativeembodiment, processor 63 is specially designed hardware for controllingthe operations of router 60. Memory 62 can be non-volatile RAM and/orROM. However, there are many different ways in which memory could becoupled to the system.

The interfaces 68 are typically provided as interface cards (sometimesreferred to as “line cards”). Generally, they control the sending andreceiving of data packets over the network and sometimes support otherperipherals used with the router 60. Among the interfaces that may beprovided are Ethernet interfaces, frame relay interfaces, cableinterfaces, DSL interfaces, token ring interfaces, serial interfaces,and the like. In addition, various high-speed interfaces may be providedsuch as fast Ethernet interfaces, Gigabit Ethernet interfaces, ATMinterfaces, HSSI interfaces, POS interfaces, FDDI interfaces and thelike. Generally, these interfaces may include ports appropriate forcommunication with the appropriate media. In some cases, they may alsoinclude an independent processor and, in some instances, volatile RAM.The independent processor may control such communications intensivetasks as packet switching, media control, and management. By providingseparate processors for the communications intensive tasks, theseinterfaces allow the master microprocessor 61 to efficiently performrouting computations, network diagnostics, security functions, etc.Router 60 may further include a packet memory 72 for intermediatestorage of packets forwarded by the router.

Although the system shown in FIG. 5 is one specific router usable inconnection with the present invention, it is by no means the onlyarchitecture on which the present invention can be implemented. Forexample, an architecture having a single processor that handlescommunications as well as routing computations is often used. Further,other types of interfaces and media may also be used with the router.

Regardless of a network device's configuration, it may employ one ormore memories or memory modules (including memory 62) configured tostore program instructions for the network management operationsdescribed herein. The program instructions may control the operation ofan operating system or one or more applications, for example. Theprogram instructions and operating system may be stored on any of themedia discussed in connection with the computer system of FIGS. 3 and 4,for example.

In one embodiment, the present invention operates in conjunction withSNMP which is described in Case, et al., “A Simple Network ManagementProtocol (SNMP),” RFC 1157, (IETF May 1990), the contents of which areincorporated by reference herein. As shown in FIG. 1, a network controlentity (e.g., SNMP manager) 16 resides on a network management station10. Agent entity 17 resides on other nodes 11, 12, 14, 15 of the networkmanaged by the manager 16. Manager 16 and agents 17 interact accordingto a protocol defined by SNMP. The SNMP manager 16 may set systemparameters, e.g., TCP/IP parameters at the node occupied by agent 17.

The SNMP manager 16 may include one or more command generators andnotification receivers. The manager 16 may further comprise a dispatcherwhich includes a PDU dispatcher, and transport mapping system, alongwith a message processing subsystem, and a security subsystem. Themanager 16 is operable to query agents 17, get responses from agents,set variables in agents, and acknowledge asynchronous events fromagents. The agent 17 may include a dispatcher, message processingsubsystem, and a security subsystem along with a command responderapplication, access control, notification originator application, andproxy forwarder application. The notification originator applicationgenerates SNMP messages containing Notification-Class PDUs (e.g., TrapPDU or Inform PDU). The command responder and notification originatorapplications are in communication with MIB instrumentation. The agent 17stores and retrieves management data as defined by the ManagementInformation Base (MIB) 18 and can asynchronously signal an event to themanagement station 10. It is to be understood that the managementstation 10 and nodes 11, 12, 14, 15 shown in FIG. 1 and described hereinare only one example of a network and that the manager and agents mayhave configurations other than shown and described herein, withoutdeparting from the scope of the invention. Furthermore, managementprotocols other than SNMP may be used.

As previously described, the Management Information Base (MIB) 18 isaccessible to SNMP manager 16 to facilitate managing networkinformation. MIB 18 includes object identifiers (OIDs) that identifyobjects storing particular pieces of information about networkoperation. Each object includes the OID and a object value which isindicative of network operation at a particular node. An MIB 18 directlyaccessible to agent 17 stores MIB objects for the node of the agent.Each object includes the OID and the object value. The MIB 18 is acollection of definitions, which define the properties of the managedobject within the device to be managed. MIB contents are described inMcCloghrie, et al., “Management Information Base for Network Managementfor TCP/IP-Based Internets: MIB-II”, (IETF March 1991), the contents ofwhich are incorporated by reference herein. Examples of MIB objectsinclude things such as: the number of outbound packets that could not betransmitted due to errors, the length of the output packet queue, textstring indicating the physical location of the node, etc.

Typically, there are many instances of each managed object type within amanagement domain. The method for identifying instances specified by theMIB module does not allow each instance to be distinguished amongst theset of all instances within a management domain. Instead it allows eachinstance to be identified only within some scope of context, where thereare multiple such contexts within the management domain. Often a contextis a physical device, or a logical device, although a context can alsoencompass multiple devices, or a subset of a single device, or even asubset of multiple devices, but a context is always defined as a subsetof a single SNMP entity. Thus, in order to identify an individual itemof management information within the management domain, its contextNameand contextEngineID must be identified in addition to its object typeand its instance. For example, the managed object type ifDescr isdefined as the description of a network interface. To identify thedescription of a device's first network interface, five pieces ofinformation are needed, the snmpEngineID of the SNMP entity whichprovides access to the management information at the device, thecontextName, the contextEngine ID, the managed object type (e.g., ifDescr), and the instance. Since the notification contains objects thatare specified in the MIB definition, the instances of the object will beborrowed when the objects within the notification are modified, asdescribed below.

The management station 10 interacts with the agents 17 using the SNMPprotocol. This protocol allows the management station to query the stateof an agent's local objects, and change them if necessary. Most of SNMPconsists of this query-response type communication. However, sometimesevents happen that are not planned. For example managed nodes can crashand reboot, interfaces can go down and come back up, or congestion canoccur. When an agent 17 notices that an event of interest to an NMS hasoccurred, it immediately reports the event to all management stations 10in its configuration list. This report is called an SNMP notification.The report typically states that some event has occurred. It is up tothe management station 10 to then issue queries to find out all thedetails.

When an application decides to send a notification, it may call one ofthe following functions, for example:

snmp:send_notification(Agent, Notification, Receiver [NotifyName,Varbinds, ContextName])

The agent 17 may then perform a get operation to retrieve the objectvalues which are defined in the notification specification. Thenotification is sent to all managers 16 defined in the target and notifytables, either unacknowledged as Traps, or acknowledged as Informrequests.

FIG. 6 is a flowchart illustrating a process of the present inventionfor specifying objects to be contained within the notification. Themethod is preferably performed by software, however, the method may alsobe implemented in hardware. The method is preferably performed by themanagement station 10, however, it may be performed by one of the agents17, or any other device in the network.

At step 100, the network management station 10 sends a Get or Getnextrequest to all of the agents 17 asking for a list of notifications thatit supports. The request may also ask for the associated variablebindings (varbinds) (i.e., OID+value), or a separate request may besent. The agents 17 then respond to the management station 10 with alist of notifications it supports (step 102). The agent 17 may send atable as shown in FIG. 7, listing the notifications that it currentlysupports along with a table, shown in FIG. 8, listing the notificationvarbinds. The first table may include, for example, link up, link down,ciscoPingCompletion, or any other event that results in a notificationbeing sent from the agent 17, such as authentication failure, coldstart, warm start, neighbor loss, (FIG. 7). It is to be understood thatnotifications may be supported for events other than those listedherein. The second table includes a list of varbinds for eachnotification supported by the agent (FIG. 8). Each varbind includes anobject identifier (OID) and the corresponding value (as describedabove). The management station 10 next tells each agent 17 which objectsto include in each of the notifications and the order of the objects(step 104). The management station 10 may provide this information as aMIB containing a modified list of varbinds, as shown in FIG. 9, forexample. FIG. 9 shows a portion of a table containing a modified varbindlist and the corresponding notification index and varbind index. Theagent's notifications originally contained the following varbinds:ifIndex; if Descr; ifType; ciscoPingCompleted; ciscoPingSentPackets; andciscoPingReceivedPackets. The management station added the followingvarbinds: ifAdminStatus and ifOperStatus. It also changed the locationof the original three varbinds to insert the two new varbinds. The newlist of varbinds may include additional varbinds or change the contextof the existing varbinds. When an event occurs, the agent 17 sends tothe management station 10 a notification containing the varbindsrequested by the management station (steps 106 and 108).

Although the present invention has been described in accordance with theembodiments shown, one of ordinary skill in the art will readilyrecognize that there could be variations made to the embodiments withoutdeparting from the scope of the present invention. Accordingly, it isintended that all matter contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

1. A method for configuring contents of a network managementnotification, comprising: sending a request from a management station toat least one agent for a list of notifications supported by the agent;receiving at the management station the list of notifications supportedby the agent, each of the notifications having an associated list ofobjects to include in notifications generated by the agent; sending amessage from the management station to the agent instructing the agentto modify said list of objects associated with at least one of thenotifications so that the notification generated at the agent comprisesthe modified list of objects in an order specified by the managementstation; and receiving from the agent a notification containing themodified list of objects in the order specified in the message sent fromthe management station, upon occurrence of an event; wherein the messagefrom the management station specifies a list of variable bindings toinclude in at least one of the notifications supported by the agent. 2.The method of claim 1 wherein sending a message comprises utilizing aSNMP protocol.
 3. The method of claim 1 wherein receiving a list ofnotifications comprises receiving a management information base.
 4. Themethod of claim 3 wherein sending a message comprises sending a modifiedmanagement information base.
 5. The method of claim 1 wherein receivinga list of notifications comprises receiving a list of objects associatedwith each of the notifications.
 6. The method of claim 5 wherein sendinga message comprises adding new objects to the notification.
 7. Themethod of claim 5 wherein sending a message comprises reordering theobjects in the notification.
 8. The method of claim 1 wherein receivinga list of notifications comprises receiving a list of variable bindingsfor each of the notifications.
 9. The method of claim 1 wherein sendinga request comprises sending a Get request.
 10. The method of claim 1wherein receiving a notification comprises receiving a Trap message. 11.The method of claim 1 wherein receiving a notification comprisesreceiving an Inform message.
 12. The method of claim 1 wherein sending amessage to the agent comprises sending a management information basecontaining a modified list of variable bindings.
 13. The method of claim12 wherein the modified list of variable bindings comprises new variablebindings.
 14. The method of claim 12 wherein the modified list ofvariable bindings comprises a new context of existing variable bindings.15. The method of claim 1 wherein sending a message to the agentcomprises creating a new management information base.
 16. The method ofclaim 15 wherein creating a new management information base compriseschanging the location of one or more original variable bindings toinsert one or more new variable bindings.
 17. The method of claim 1wherein sending a request comprises sending a request for variablebindings associated with each of the notifications.
 18. A computerprogram product for configuring contents of a network managementnotification, comprising: code that sends a request from a managementstation to at least one agent for a list of notifications supported bythe agent; code that receives at the management station a list ofnotifications supported by the agent, each of the notifications havingan associated list of objects to include in notifications generated bythe agent; code that sends a message from the management station to theagent instructing the agent to modify said list of objects associatedwith at least one of the notifications so that the notificationgenerated at the agent comprises the modified list of objects in anorder specified by the management station; code that receives anotification containing the modified list of objects in the specifiedorder upon occurrence of an event; and a computer-readable storagemedium for storing the codes, wherein the computer-readable storagemedium is not a data signal embodied in a carrier wave; wherein themessage from the management station specifies a list of variablebindings to include in at least one of the notifications supported bythe agent.
 19. The computer program product of claim 18 wherein thecomputer readable medium is selected from the group consisting ofCD-ROM, floppy disk, tape, flash memory, system memory, and hard drive.20. The computer program product of claim 18 wherein the managementstation comprises a SNMP manager.
 21. The computer program product ofclaim 18 further comprising code that requests information onnotifications from the agents.
 22. A system for configuring contents ofa network management notification, comprising: a processor at amanagement station that receives information specifying contents ofnotifications supported by an agent, each of the notifications having anassociated list of objects to include in notifications generated by theagent, sends instructions to the agent to modify said list of objectsassociated with at least one of the notifications so that thenotification generated at the agent comprises the modified list ofobjects in an order specified by the management station, and receivesfrom the agent a notification containing the modified list of objects inthe order specified in the message sent from the management station uponoccurrence of an event; and a storage medium having said list of objectsassociated with the notifications stored thereon wherein the messagefrom the management station specifies a list of variable bindings toinclude in at least one of the notifications supported by the agent. 23.A system for configuring contents of a network management notification,comprising: means for sending a request from a management station to atleast one agent for a list of notifications supported by the agent;means for receiving information specifying contents of notificationssupported by the agent within a network at the management station, eachof the notifications having an associated list of objects to include innotifications generated by the agent; means for sending instructionsfrom the management station to the agent to modify said list of objectsassociated with at least one of the notifications so that thenotification generated at the agent comprises the modified list ofobjects in the order specified by the management station; and means forreceiving from the agent a notification containing the specified objectsin the specified order upon occurrence of an event; wherein the messagefrom the management station specifies a list of variable bindings toinclude in at least one of the notifications supported by the agent. 24.A system for sending SNMP notification from an agent to a managementstation, comprising: a processor that receives a message from themanagement station instructing the agent to modify a list of objectsassociated with a notification so that the notification generated at theagent comprises the modified list of objects in the order specified bythe management station, modifies said list of objects for thenotifications to include in the specified order, and sends anotification containing the modified list of objects in the specifiedorder upon occurrence of an event; wherein the message from themanagement station specifies a list of variable bindings to include inthe notification; and a storage medium for storing the notificationssupported by the agent and the list of variable bindings.